Coke-tree breaker



1945. A. K. KNUDSEN ET AL 2,370,175

COKE- TREE BREAKER Filed June 20, 1941 Patented Feb. 27, 1945 COKE-TREEBREAKER Arthur K. Knudsen, Oak Park, .and Arthur V. Sampsel, SpringValley,.lll,, assignors to Sears, Roebuck and Co., Chicago, 111., acorporation of New York Application June 20, 1941, Serial No. 398,866

3 Claims.

elude a hold-fire switch and/or an out-fire switch, means for agitatingthe coke-tree forming in the burner. This is of importance whereeverstokers use coal. of high coking characteristics. Such coal forms acoke-tree in the burner, and this-coke-tree increases in size as morecoal is fed, until it blocks further combustion and puts the fire out.The coke-tree, if permitted, will substantially fill the fire-box and,when it cools, it expands and is likely to break the walls of thefirebox. Moreover, it is a difficult and time-consuming task to cleanthe fire-box of the accumulated coke.

By means of the apparatus about tobe described, the coke-tree whichforms during, and between successive feedings of coal is. broken andmixed with green coal which. burns to a sufficiently high temperature toalso burn the coke.

In the past, it has been the practice, where furnaces were equipped withsuch agitators, to locate the agitator within the furnace. made accessdifilcult and inconvenient. Moreover, it has been the practice to soconnect the agitator with the stoker that when the agitator becameinoperative, the stoker also was inoperative and the stoker could not bemade to operate until after the agitator again became operative.

In accordance with the present invention, the agitating member ismounted outside of the furtrace and in a position where it is easilyaccessible for repair or adjustment without necessitating opening of thefurnace. Another important feature is that the stoker is independent ofthe operation of the agitator, so that should the agitator be put out ofoperation for one reason or another, the stoker will continue to operateas if nothing had happened. v

Another disadvantage of past agitator constructions is that there is alikelihood. of the agitators stopping within the burner or fire-box andbecoming burned, or of the cokes freezing around the agitator so as toprevent the agitator from operating the next time it is supposed tooperate. With the present construction, as will be seen, the agitator isnecessarily removed from the fire at the close of each agitatingoperation.

Further objects and advantages of our invention will appear as thedescriptionproceeds.

The invention will be better understood upon companying drawing, inwhich:

This

Fig. l is a schematic view, partly in section, of an agitator'andcontrol therefor, embodying features of our invention, taken partlyasindicated by the line i--l in Fig.4.

Fig. 2 is a broken elevation showing-an agitator in a stoker andfurnaceassem-bly.

Fig. 3 is asection-elevation taken as indicated by the line 3-3 in Fig.1.

Fig. 4 is a diagrammatic plan viewtaken as indicated by the line4--4.in. Fig. 1. -:Fig- 5 is asectional viewtakeni as indicated by theline 55 in Fig. 1.

Referring more particularly to Fig. 1,. showing one form of agitatorsystem embodying. our invention, there is operated either from the line6 or other energy sourcea clock. (not shown) which turns a cami.l,,.,haying. vanes i2 and r0- tating once an hour. for example, or anyother suitable period. .A hand switch .1 and a fuse 8 may bedisposedinsaid line. be operated by the sameclock operating. theholdfireswitch, if such hold-fire switch is used in the stokerinstallation to which our invention is applied. The number of vanes l2maybe varied as desired, say from 1 to 2 to 4, depending of course onthe frequency with which. it is considered desirable to agitate thefire. This frequency may vary with the coking characteristics of thefuel, the size of the fire, and for other reasons. Each vane is designedand arranged to close a switch 1-4,. mercury tube or other suitableswitch for any desired period, say, one second. This period is mentionedby wayof example because as will be understood by those skilled in theart the durationmay be varied. The switch I4 is normally held open as bya spring 15,1110 an extent limited by the inherent shape of the switchblade or as-by a stop IS. The switch I4 is in series with a relay coil18 which is in series with a transformer secondary coil l9.- When theswitch I4 is closed, the relaycoil l8 closes a relay switch 20, therebyclosing a circuit which includes a motor 2|.

Connected to the motor 2| as through reduction gearing, (not shown) is acam 22 which is rotated at the rate of,.say, once in .five seconds. Thiscam has a make shoulder 24. which is engageable with av bell crank'lever25 pivoted at 26, to'tilt and close a mercury tube switch 28.

This tube normallyrests in the position shown,

as on a stop-.29, with the-switch open. At the moment the relay switch20 closes, the cam 22 is arranged substantially as shownin Fig. 1,,sothat, in a fraction of a second, .if desired, i. e., substantially whilethe switch 20 is being fully The cam ll. could closed, the mercuryswitch 28 will be tilted and closed. Inasmuch as the switch I4 andconsequently the switch are closed each time for one second and the cam22 is rotated by power at the rate of one revolution in five seconds, itfollows that the cam 22 will rotate one-fifth of a revolution while theswitch 20 remains closed. Then the switch 20 will open because by thattime the switch l4 has opened, thereby de-energizing the relay coil l8controlling the relay switch 20. However, the circuit through the motor2| is not broken by virtue of the opening of the switch 20, because,before the switch 2:: is opened, the outer surface 22a of the cam 22 hasbecome engaged with the lever 25 and therelore has not only closed thetube switch 28, as explained above, but maintains the switc 26 closed,and it will be observed that the tube switch 20 is in parallel with andtherefore bypasses the relay switch 20. The motor 2| therefore continuesill operation, as does the cam .2, and the lever 25 continues to ride onthe outer surface of said cam.

The cam 22 has, a cavity 30, and when the lever 25 drops from the breakpoint 3| into the cavity, the tube switch 28 swings to open position,opening the motor circuit, the relay switch 25 at such time being open.Since the cam 22 is turned by the motor at the rate or once in fiveseconds, whereas the switch 20 is closed for only one second and atintervals of fifteen minutes, in the example chosen for illustration,and since that interval is not completed until after the projection ofthe lever 25 into the cavity 30, the opening of the motor circuit atsuch projection is assured.

The motor 2| does not stop immediately, but, rather, together with thereduction gearing and cam 22, it coasts to such an extent as to rotatethe cam 22 a fraction of a turn. The cam 22 is so designed that it willhold the switch 28 closed longer than one second, i. e., longer than theswitch 20 is closed. The travel of the cam 22 from the end of the coastof the cam to the time of closing of the switch 28 should consume lessthan one second because, as noted above, the rotation of the cam at thispoint results from the closing of the relay switch 20, and it isnecessary that the lever 25 reach the outer surface of the cam andthereby close the switch 28 before the switch 20 opens, as stated above.Otherwise the cam would stop when the switch 20 opens, and thus theagitator, presently to be described, would not be operated as often asit should, i. e., as often as the switch 20 closes. The coasting cavity30 in the cam 22 may be designed by cut and try methods, simply byrunning and stopping the motor 2| a few times and observing the travelof the cam 22 during each coasting period.

Connected to the cam 22 in any suitable manner, as indicateddiagrammatically at 33, is a crank disc 34 having a crank pin 35 towhich is joined a pitman 31 passing through an opening 38 in the outerwall 39 of a compartment 4| which may intervene portions of the Windbox42. The wall 39 is preferably detachably connected, as to the wind-box,to render the interior of the compartment accessible for inspection,adjustment and repair. The pitman in turn is joined as at 43 to anagitator bar 45 pivotally suspended as at 46 outside of the burner orretort 41, to which a coal feed tube 49 leads. A rubber, leather orother suitable flexible boot the crank disc 34.

or shroud 50 is attached about the opening 38 and has a preferablyair-tight fit about the Pitman 31 so as to move therewith and yet keepdust and the like from entering the compartment through the opening 38.The agitator 45 comprises a driving part 52, to which the pitman isconnected, and a driven part in the form of a prong or prod 53. The part52 is adapted to move entirely within the compartment, but the prod isadapted to protrude completely through an opening 54, preferablyadjacent the feed tube 49, and to be completely withdrawn from theburner to a position where it is protected from the heat, as shownrespectively in full and dotted lines in Fig. 1. The tip or end 56 ofthe prod, where it enters the burner, i. e., at the opening 54, ispreferably sufliciently below the bottom of the coke tree 51 to enablesaid tip to force up a substantial quantity of green coal as well asbreak up the tree. The prod is arranged preferably so as to strike thetree substantially at the axis of the tree, and substantially crumblesthe tree at each operation.

A breaking of any part of the tree will effect the breaking up ofsubstantially all of it. The burner wall at the opening 54 is preferablysufiiciently close to the prod 53 to wipe riddlings, ash, etc., from theprod upon each return movement of the latter, thus substantiallypreventing any foreign matter from entering the compartment through theopening.

It will be observed that the opening 54 extends outwardly somewhat,providing a passage for the escape into the feed tube 49 of anyriddlings,

:ash, etc., which may tend to enter the c0mpartment 4| where the prod islocated. This opening is not sufficiently wide ao allow coal to enterthe compartment.

Referring again to the cam 22, it will be observed that the outersurface of the cam maintains the switch 28 closed notwithstanding thefact that the switch 20 is open, and thereby closes the circuit of themotor 2| which accordingly continues to rotate the cam 22 and of courseWhen the bell crank lever 25 jumps off the break point 3| of the cam 22,the switch 28 opens, and since the switch 20 at such time is open andwill continue to be open for a while thereafter, the circuit includingthe motor 2| is opened. As stated before, the reduction gearing willcoast until the parts are arranged as shown in Fig. l and, during thiscoasting, the agitator prod 53 is withdrawn completely from the retort41. The cam 22 cannot stop except in the position shown in Fig. l, andconsequently the agitator prod 53 cannot stop until its end 56 iswithdrawn to a position where only green coal is located.

With reference to the relative operations of the switches 20 and 28, itis to be noted that it is desirable to have the agitator 45 rest betweenagitations to give its prod 53 an opportunity to cool, and this is madepossible by withholding closing of the switch 2|) for an interval afterthe cam '22 stops. will be in continuous motion, which may beunnecessary or undesirable. By providing the arrangement above noted byway of example, it is apparent that the period of a complete cycle ofcontinuous motion of the cam, and hence of the agitator, is somewhatover five seconds, due to the coasting time which obviously is slowerthan the motor running time. With the switch 20 closing every fifteenminutes, for example,the interval Unless this is done the agitator ofrest will be short of fifteen minutes by slightly more than fiveseconds. 'By varying the frequency of closing the switch 20, as byvarying the speed of the cam H or the number of its vanes l2, or thespeed of rotation of the cam 22 or the length of the cavity 30, ormaking any other suitable changes, the waiting interval can be made onceor more per hour or once every few hours or otherwise as desired.

Fig. 2 shows more or less diagrammatically the general assembly of astoker 60, a furnace GI and a part of the coke-tree agitator mechanism.The agitator and its operating mechanism are outside and readilyaccessible for repair or other attention, for which purpose the wall 39is preferably removably mounted. As will be appreciated from theforegoing, the agitator and its operating machanism are entirelyindependent of the stoker and hence may be stopped and repaired withoutinterfering with the operation of the Stoker, and likewise the stokermay be stopped or given any desired attention without afiecting theoperation of the agitator or its operating mechanism.

Various modifications may suggest themselves to those skilled in the artwithout departing from the spirit of our invention, and, hence, we donot wish to be restricted to the specific form shown or uses mentioned.

We claim:

1. A device of the class described, comprising a circuit includingmotive means, a pair of normally open switches, each in parallel withthe other and in series with said motive means, a relay operativeintermittently to close one of said switches, means rendered operativeby the closing of the relay switch to close the other switch,

means for maintaining said other switch closed for a limited periodafter said relay switch opens, a furnace retort adapted to consume solidfuel having coke-tree forming characteristics,- and means operativelyconnected to said motive means and projectable thereby into and out ofengagement with a coke-tree in said retort while said other switch isclosed, said projectable means being out of engagement with the treewhen said other switch is open.

2. A device of the class described, comprising a solid fuel retort, acoke-tree breaker projectable into and out of engagement with a tree insaid retort, motive means for said breaker, a control for said motivemeans, means momentarily operative for initiating operation of saidmotive means, said motive means including means operative formaintaining said control in operation for a period during which saidbreaker moves into and out of engagement-with the tree, and means forrendering said control inoperative at the end of said period.

3. A device of the class described, comprising a solid fuel retort, acoke-tree breaker projectable into and out of engagement with a tree insaid retort, motive means for said breaker, means affording a supply ofenergy to said motive means, means connecting said supply to said motivemeans, rendering the latter operative to project said breaker intoengagement with the tree, means for disconnecting said supply from saidmotive means during said engagement, said motive means coasting uponsuch disconnection to such an extent as to withdraw said breaker out ofsaid retort.

. ARTHUR K. KNUDSEN. ARTHUR V. SAMPSEL.

